Doc: Fixed typo in QDialog.

Task-number: QTBUG-31493

Change-Id: Ie112f601d629c794842d746e7b9c96849c74bdf6
Reviewed-by: Sergio Ahumada <sergio.ahumada@digia.com>
Update LICENSE.PREVIEW.COMMERCIAL license

Change-Id: I8af7630ec54e1a9d4b063e8278df5e75d2abf97e
Reviewed-by: Akseli Salovaara <akseli.salovaara@digia.com>
Reviewed-by: Iikka Eklund <iikka.eklund@digia.com>